Producing rubber-like compounds.



"UNITED STATES PATENT onnion.

HENRY STALAY ARTHUR HOLT, OF LUDWIGSHAFEN-ON-THE-RHINE, GERMANY, AS-

SIGNOR TO BADISCHE ANILIN & SODA FABRIK, OF LUDWIGSHAFEN-ON-THE-RHINE,

GERMANY, A CORPORATION.

PRODUCING RUBBER-LIKE COMPOUNDS.

No Drawing.

To all whom it may concern:

Be it known that I, HENRY STALAY- AR- THUR HOLT, a subject of the King of England, residing at Ludwigshafen-on-the- Rhine, Germany, have invented new and useful Improvements in Producin Rubber- Like Compounds, of which the f0 lowing is a specification.

The specification of, British Patent No.

254/l0 states that erythrene (divinyl) can be converted into a substance resembling natural rubber by the application of heat, either in the absence or in the presence of an agent which assists in the polymeriza-.

15 tion, but there is no special definition or description of any substance which may be employed as such agent. Further, the specification of British Patent No. 17 ,734/10 describes the production of such rubber- 20 like products by heatingisoprene, and it is stated that the addition of indifferent substances, or of catalytic agents, of either neutral, acid or alkaline reaction, does not interfere with the polymerization, but this specification does'not contain any specific definition, or description, of a catalytic agent.- It is also known generally that isoprone and its homologues, such for instance as. 'dimethyl-buthadiene, can be polymerized yielding substances resembling rubber, and

it has been suggested to employ certain compounds, such for instance as alcoholic potash, or soda, concentrated aqueous hydrochloric acid, and calcium chlorid solution, in

the belief that such compounds would assist in the polymerization, but no proof has been forthcoming that such compounds favor the polymerization,- or. in other words, induce the formation of a larger quantity of the substancesire'sembling rubber than would be formed if such compounds were not present.

I have foundthat alcohols, aldehydes, alkalies, and ox'ids and hydroxids which act as alkalies, when added, even though only slightly soluble-in isoprene, and whether employed as such or in the presence of water, actually decrease the yield, and further that the use of large-quantities of strong acids does not accelerate the polymerization,

Specification of Letters Patent.

Patented May 27, 1913.

- Application filed December 9, 1911. Serial No. 664,874.

but deteriorate the obtained. I have found that sulfur, when employed lnminute quantities, brings about a consid, erable acceleration of thepolymerization tov form the desired. substance resembling rub-5 her, whereas if large quantities be employed:

quality of the productto such an improvement in the reaction is not 3 brought about.

I Thus, for instance, an ada d1t1on of one-fifth of one-per cent. of sulfur '1 about doubles the yield of raw rubber-like substance obtainable from isoprene, whereas if two per cent. be employed a much smaller yield of the product is obtained and this produce is very impure and, even after repeated solution and precipitation from benzene, cannot be obtained in. the desired state of purity.

The following is an example of how my invention can be carried into practical effect,

but the invention is not confined to this exis the lowest member, in the presence of a 35 very small quantity of sulfur.

2. The process of producing compounds resembling rubber by heating isoprene in the presence of about one-fifth of one pe cent. of sulfur.

In testimony whereof I have hereunto set my hand in the presence of two subscribing witnesses.

ARTHUR HOLT.

Witnesses:

J. Anno LLOYD, A. O. TITTMANN. 

